The present disclosure relates to materials and processes for producing multilayer constructs useful for forming electrochemical test strips, as well as devices, such as medical devices, utilizing the same. In particular, multi-layer constructs comprising a non-conductive substrate layer, a conductor layer, and an oxidized Transparent Conducting Oxide (TCO) protective layer are provided. The multi-layer constructs so produced impart superior electrochemical response while maintaining desired mechanical properties, and will be described with particular reference thereto. However, it is to be appreciated that the present disclosure is also amenable to other like constructs and applications.
The present disclosure also relates to processes and apparatuses for optimizing the single pass production of multilayer constructs including metal/Transparent Conducting Oxide (TCO) multilayers. In particular, multilayer constructs are used as an electrochemical test strip, such as a biosensor, and will be described with particular reference thereto. However, it is to be appreciated that the present disclosure is also amenable to other like processes and apparatuses.
Electrochemical test strips can be used in several applications, such as various metering devices for testing and/or determining certain characteristics and/or the presence of analytes in a specimen. In this regard, the test strips can be used as biosensors for measuring the amount of an analyte (e.g., glucose) in a biological fluid (e.g., blood). For example, a glucose biosensor is an analytical device for detecting the analyte, glucose, in the blood. These biosensors use a redox enzyme (e.g., glutathione peroxidases (GPX), nitric oxide synthase (eNOS, iNOS, and nNOS), peroxiredoxins, super oxide dismutases (SOD), thioredoxins (Trx), and the like) in a reagent layer, as the biological component responsible for the selective recognition of the analyte of interest (e.g., glucose).
The biological fluid sample is introduced into the reagent layer of a reaction chamber of the test strip. The test strip is connected to a measuring device such as a meter for analysis using the test strip's electrodes. The analyte in the sample undergoes a reduction/oxidation reaction at the working electrode (where the redox enzyme is located) while the measuring device applies a biasing potential signal through the electrodes of the test strip. The redox reaction produces an output signal in response to the biasing potential signal. The output signal usually is an electronic signal, such as potential or current, which is measured and correlated with the concentration of the analyte in the biological fluid sample.
Electrochemical test strips of this type are made from multilayer constructs. An important feature of these multilayer constructs is that their materials have a reduced sensitivity to heat, humidity and degradation, while maintaining mechanical robustness and good electrical conductivity. These materials are desirably less affected by environmental factors such as air and water, and are mechanically robust while maintaining electrochemical preferentiality.
It would be desirable to develop new methods and processes to produce fully-fabricated multilayer constructs for use in sensor applications. This could result in ready-made multilayer constructs having improved electrochemical and mechanical properties, which could be used in biosensors for several different applications.